Introduction

The Rosewill SilentNight 500 W is a fanless power supply with the 80 Plus Platinum certification, targeted to users building a quiet computer. It also comes with a modular cabling system. Let’s see how this new release fared on our tests.

The modular cabling system from this power supply has four connectors and can be used by any type of cable. Three cables come permanently attached to the power supply. These cables are protected with nylon sleeves, which come from inside the unit. This power supply comes with the following cables:

Main motherboard cable with a 20/24-pin connector, 22.4” (57 cm) long, permanently attached to the power supply

One cable with two ATX12V connectors that together form an EPS12V connector, 26” (66 cm) long, permanently attached to the power supply

One cable with two six/eight-pin connectors for video cards, 21.2” (54 cm) to the first connector, 5.1” (13 cm) between connectors, permanently attached to the power supply

One cable with two six/eight-pin connectors for video cards, 19.7” (50 cm) to the first connector, 5.1” (13 cm) between connectors, modular cabling system

One cable with four SATA power connectors, 19.7” (50 cm) to the first connector, 5.1” (13 cm) between connectors, modular cabling system

One cable with two SATA and two peripheral power connectors, 19.7” (50 cm) to the first connector, 5.1” (13 cm) between connectors, modular cabling system

One cable with three peripheral power connectors and one floppy disk drive power connector, 19.7” (50 cm) to the first connector, 5.1” (13 cm) between connectors, modular cabling system

All wires are 18 AWG, which is the minimum recommended gauge, except for the +12 V (yellow) and ground (black) wires used on the ATX12V/EPS12V and main motherboard cables, which are thicker (16 AWG).

The number of connectors is outstanding for a 500 W power supply.

click to enlargeFigure 3: Cables

Let’s now take an in-depth look inside this power supply.

A Look Inside the Rosewill SilentNight 500 W

We decided to disassemble this power supply to see what it looks like inside, how it is designed, and what components are used. Please read our “Anatomy of Switching Power Supplies” tutorial to understand how a power supply works and to compare this power supply to others.

On this page we will have an overall look, and then in the following pages we will discuss in detail the quality and ratings of the components used.

click to enlargeFigure 4: Top view

click to enlargeFigure 5: Front quarter view

click to enlargeFigure 6: Rear quarter view

click to enlargeFigure 7: The printed circuit board

Transient Filtering Stage

As we have mentioned in other articles and reviews, the first place we look when opening a power supply for a hint about its quality, is its filtering stage. The recommended components for this stage are two ferrite coils, two ceramic capacitors (Y capacitors, usually blue), one metalized polyester capacitor (X capacitor), and one MOV (Metal-Oxide Varistor). Very low-end power supplies use fewer components, usually removing the MOV and the first coil.

In the transient filtering stage, this power supply has two X capacitors and two Y capacitors more than the minimum required. However, it doesn’t have an MOV, a component that is in charge of removing spikes coming from the power grid.

click to enlargeFigure 8: Transient filtering stage

On the next page, we will have a more detailed discussion about the components used in the Rosewill SilentNight 500 W.

Primary Analysis

On this page, we will take an in-depth look at the primary stage of the Rosewill SilentNight 500 W. For a better understanding, please read our “Anatomy of Switching Power Supplies” tutorial.

This power supply uses one US30K80R rectifying bridge, which is attached to the same heatsink where the active PFC and switching transistors are located. This bridge supports up to 30 A at 97° C. In theory, you would be able to pull up to 3,450 W from a 115 V power grid. Assuming 80% efficiency, the bridge would allow this unit to deliver up to 2,760 W without burning itself out (or 3,105 W at 90% efficiency). Of course, we are only talking about this particular component. The real limit will depend on all the components combined in this power supply.

click to enlargeFigure 9: Rectifying bridge

The active PFC circuit uses one IPW50R140CP MOSFET, which supports up to 23 A at 25° C or 15 A at 100° C in continuous mode (note the difference temperature makes), or 56 A at 25° C in pulse mode. These transistors present a 140 mΩ maximum resistance when turned on, a characteristic called RDS(on). The lower the number the better, meaning that the transistor will waste less power, and the power supply will have a higher efficiency.

The active PFC circuit is managed by an NCP1653A active PFC controller.

click to enlargeFigure 10: Active PFC controller

The output of the active PFC circuit is filtered by one 470 µF x 400 V Japanese electrolytic capacitor, from Chemi-Con, labeled at 105° C.

click to enlargeFigure 11: Capacitor

In the switching section, two IPP50R199CP MOSFETs are employed using a resonant configuration. Each transistor supports up to 17 A at 25° C or 11 A at 100° C in continuous mode or up to 40 A at 25° C in pulse mode, with a maximum RDS(on) of 199 mΩ.

click to enlargeFigure 12: The two switching transistors, the active PFC diode, and the active PFC transistor

Secondary Analysis

As one would expect in a high-efficiency power supply, the Rosewill SilentNight 500 W uses a synchronous design, where the Schottky rectifiers are replaced with MOSFETs. Also, the reviewed product uses a DC-DC design in its secondary. This means that the power supply is basically a +12 V unit, with the +5 V and +3.3 V outputs produced by two smaller power supplies connected to the main +12 V rail. Both designs are used to increase efficiency.

The +12 V output uses four IPP023N04N G MOSFETs, each one supporting up to 90 A at 100° C in continuous mode, or up to 400 A at 25° C in pulse mode, with a maximum RDS(on) of 2.3 mΩ.

click to enlargeFigure 14: The +12 V transistors

As explained, the +5 V and +3.3 V outputs are produced by two DC-DC converters, which are situated on the same printed circuit. Each converter is controlled by an NCP1587A integrated circuit. Each output uses two IPD040N03L G MOSFETs, each one supporting up to 90 A at 25° C or up to 76 A at 100° C in continuous mode and up to 400 A at 25° C in pulse mode, with a maximum RDS(on) of 4 mΩ.

click to enlargeFigure 15: The DC-DC converters

click to enlargeFigure 16: The DC-DC converters

The outputs of the power supply are monitored by the SF29601 integrated circuit. Since this is a proprietary chip from Super Flower, there is no datasheet publicly available for it, so we can’t comment on the protections it supports.

The secondary has solid and regular electrolytic capacitors, manufactured in Japan by Chemi-Con, and labeled at 105° C.

click to enlargeFigure 17: Capacitors

Power Distribution

In Figure 18, you can see the power supply label containing all the power specs.

click to enlargeFigure 18: Power supply label

As you can see, this unit has a single +12 V rail configuration, so there is not much to talk about here.

Let’s find out how much power this unit can deliver.

Load Tests

First, we tested this power supply with five different load patterns, trying to pull around 20%, 40%, 60%, 80%, and 100% of its labeled maximum capacity (actual percentage used listed under “% Max Load”), watching the behavior of the reviewed unit under each load. In the table below, we list the load patterns we used and the results for each load.

If you add all the powers listed for each test, you may find a different value than what is posted under “Total” below. Since each output can have a slight variation (e.g., the +5 V output working at 5.10 V), the actual total amount of power being delivered is slightly different than the calculated value. In the “Total” row, we are using the real amount of power being delivered, as measured by our load tester.

The +12VA and +12VB inputs listed below are the two +12 V independent inputs from our load tester. During this test, the +12VA and +12VB inputs were connected to the power supply’s single +12 V rail. (The +12VB input was connected to the power supply EPS12V connector.)

Input

Test 1

Test 2

Test 3

Test 4

Test 5

+12VA

3.5 A (42 W)

7.5 A (90 W)

10.5 A (126 W)

14 A (168 W)

17.5 A (210 W)

+12VB

3.5 A (42 W)

7 A (84 W)

10.5 A (126 W)

14 A (168 W)

17 A (204 W)

+5 V

1 A (5 W)

2 A (10 W)

4 A (20 W)

6 A (30 W)

8 A (40 W)

+3.3 V

1 A (3.3 W)

2 A (6.6 W)

4 A (13.2 W)

6 A (19.8 W)

8 A (26.4 W)

+5VSB

1 A (5 W)

1.5 A (7.5 W)

2 A (10 W)

2.5 A (12.5 W)

3 A (15 W)

-12 V

0.5 A (6 W)

0.5 A (6 W)

0.5 A (6 W)

0.5 A (6 W)

0.5 A (6 W)

Total

104.8 W

210.5 W

314.3 W

425.9 W

502.2 W

% Max Load

21.0%

42.1%

62.9%

85.2%

100.4%

Room Temp.

45.9° C

45.2° C

45.2° C

45.6° C

46.9° C

PSU Temp.

52.7° C

52.9° C

53.4° C

54.6° C

56.2° C

Voltage Regulation

Pass

Pass

Pass

Pass

Pass

Ripple and Noise

Pass

Pass

Pass

Pass

Pass

AC Power

114.8 W

227.2 W

341.4 W

468.1 W

556.8 W

Efficiency

91.3%

92.6%

92.1%

91.0%

90.2%

AC Voltage

118.0 V

117.3

115.9 V

114.8 V

113.8 V

Power Factor

0.984

0.983

0.986

0.989

0.991

Final Result

Pass

Pass

Pass

Pass

Pass

We were really impressed by the efficiency results of the Rosewill SilentNight 500 W, always above 90% at high temperatures.

Voltage regulation was also outstanding, with all voltages within 3% of their nominal values. The ATX12V specification states that positive voltages must be within 5% of their nominal values, and negative voltages must be within 10% of their nominal values.

Let’s discuss the ripple and noise levels on the next page.

Ripple and Noise Tests

Voltages at the power supply outputs must be as “clean” as possible, with no noise or oscillation (also known as “ripple”). The maximum ripple and noise levels allowed are 120 mV for +12 V and -12 V outputs, and 50 mV for +5 V, +3.3 V and +5VSB outputs. All values are peak-to-peak figures. We consider a power supply as being top-notch if it can produce half or less of the maximum allowed ripple and noise levels.

The Rosewill SilentNight 500 W provided extremely low ripple and noise levels, as you can see in the table below.

Overload Tests

Below you can see the maximum we could pull from this power supply. The objective of this test is to see if the power supply has its protection circuits working properly. This unit passed this test, since it shut down when we tried to pull more than what is listed below. During this test, noise and ripple levels were still low, with all outputs still within 3% of their nominal values.

Input

Overload Test

+12VA

26 A (312 W)

+12VB

26 A (312 W)

+5 V

10 A (50 W)

+3.3 V

10 A (33 W)

+5VSB

3 A (15 W)

-12 V

0.5 A (6 W)

Total

657.8 W

% Max Load

131.6%

Room Temp.

44.8° C

PSU Temp.

50.1° C

AC Power

749.0 W

Efficiency

87.8%

AC Voltage

111.7 V

Power Factor

0.992

Main Specifications

The main specifications for the Rosewill SilentNight 500 W power supply include:

Conclusions

We were really impressed with the Rosewill SilentNight 500 W. It is one of the best power supplies that we’ve ever reviewed.

Efficiency was always above 90%, surpassing the requirements of the 80 Plus Platinum certification by a good margin. Most power supplies we test can’t deliver the promised efficiency at high temperatures, since the tests for the 80 Plus certification are conducted at 23° C, and efficiency drops as temperature increases.

The efficiency numbers are more incredible when you take into consideration that this is a fanless power supply. Power supplies without a fan may work internally at higher temperatures, meaning lower efficiency.

Voltage regulation was superb, with all outputs within 3% of their nominal values. Noise and ripple levels were extremely low, making this unit a flawless product.

The Rosewill SilentNight 500 W competes directly with the Seasonic Platinum Fanless 520 W. This model from Seasonic has a few advantages, which include a fully modular cabling system, seven-year warranty, a depth of 6.3”/160 mm (the Rosewill model, which is 6.7”/170 mm deep, won’t fit cases that only support power supplies up to 6.3”/160 mm deep), and costs USD 10 less. The model from Seasonic also presented, on our tests, maximum efficiency that was one percentage point above Rosewill’s. The Rosewill SilentNight 500 W, however, has four six/eight-pin connectors for video cards, while the model from Seasonic has two.

While we are inclined to recommend the Seasonic Platinum Fanless 520 W over the Rosewill SilentNight 500 W because of its slight overall advantage, the model from Rosewill is an excellent product as well and will please the user who is building a silent computer and wants “the best.” Other fanless power supplies, such as the SilverStone Nightjar 500 W (80 Plus Bronze certification, USD 185), pale in comparison

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